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<br />Most of the diversion structures in the Grassy Creek Mine area are <br />associated with overland flow or small ephemeral drainages with <br />upstream watersheds of less than one square mile, and so do not <br />require certification. Consistent with applicable regulatory <br />requirements, appropriate Professional Engineer certifications are <br />provided in this submittal for those structures identified above. <br />PITS 1/2/3 <br />1) Please refer to the April 24, 1991 letter, issue number VII 23 (mistyped as <br />21) regarding Notice of Vrolation C-89-034. The pending drainage control <br />issues must be resolved. <br />Response: Question VII 23 references NOV C-89-034 and specific <br />comments from the 4/24/91 Division letter. To facilitate review, specific <br />• drainage areas are identified, Division comments are restated as <br />appropriate, and corresponding responses are presented as follows: <br />(lA) The diversion ditc/i skirting the nonlt and west sides of the Pit 6 <br />disturbed area. <br />Response (1A): The NOV stipulated that the noted drainage features <br />be properly mapped, that appropriate design calculations be developed <br />and submitted, and that a schedule be provided for modification to <br />meet design criteria. <br />The diversion ditch on the north and west sides of Pit 6, along with the <br />upland diversions will be removed and the associated disturbance <br />areas reclaimed. A vegetated drainageway has been designed and will <br />be installed to safely pass upgradient drainage through the Pit 6 <br />• reclaimed area as shown on the Postmining Drainage and Sediment <br />' Control Map, (Map R-1). In addition, drainage designs for all <br />-6- <br />